1. Field of the Invention
The present invention relates generally to container closures, and, more particularly, to an improved, easy opening, screw-cap for bottle-type containers.
2. Description of the Related Art
The problem of providing an easy and efficient opening means for containers such as bottles, has existed for decades. Conventional bottle caps, such as those disclosed in U.S. Pat. No. 4,627,548, issued in the name of Thompson and U.S. Pat. No. 4,550,843, issued in the name of Nolan, require use of a bottle opener to be removed from the bottle. This is inconvenient for most consumers.
U.S. Pat. No. 5,265,746, issued in the name of Lee and U.S. Pat. No. 4,333,578, issued in the name of Di Nunzio, disclose bottle caps having an integral opener. U.S. Pat. No. 4,782,969, issued in the name of Henning, discloses a traditional bottle cap that is designed to be twisted off.
An improvement over traditional bottle caps exists within the art, and is now known as screw-type bottle caps or twist caps. These screw caps generally consist of a cylindrical cap with a series of detendes, or grooves, placed horizontally and equally spaced along the exterior portion of the screw cap. It is these protrusions, or ridges, which the operator uses to open the screw cap. Screw caps haye become an integral part of modern society. They are used on numerous products ranging from bottled soft-drinks and water to medicine and cleaning products.
The problem with conventional screw caps is that there is not enough lateral surface area on the ridges to create mechanical interference with the user's fingers as angular torsion is applied to the ridges relative to the bottle or container to twist off the twist cap. This lack of mechanical interference with the exterior surface of the screw cap necessitates that the operator squeeze the bottle cap to increase friction with the screw cap to assist in the twisting procedure. This method of removal of the screw cap creates several problems.
First, many individuals do not have sufficient hand strength to provide sufficient pressure to the sides of the bottle cap to assist in successful removal of the cap. This is especially true for the young, elderly and infirm, as well as those with arthritis. Second, pressing one's fingers into the ridges to increase the grip causes discomfort. Third, the lack of gripping surfaces for torsional force on the screw cap increases the risk of one's hands slipping from the bottle cap. Fourth, when such slipping occurs, injury to the skin of the fingers is likely, especially when the operator has dry skin. Fifth, difficulty in opening the screw cap increases the jarring motions placed on the bottle or container, which can disrupt the contents, such as with the foam head created by carbonated beverages. All these problems cause difficulty in opening a screw cap as well as inconvenience and frustration to a large segment of the population who use them.
Examples of screw-type caps for containers such as bottle caps in the previous art include U.S. Pat. No. 4,362,639, issued in the name of Stahl, U.S. Pat. No. 4,210,251, issued in the name of Grussen, and U.S. Pat. No. 4,090,631, issued in the name of Grussen.
The '639 device attempts to improve ease of opening by utilizing gripping ribs of slightly larger than normal lateral width. This design, while slightly increasing gripping surface area, does not provide sufficient means to overcome the problems of conventional twist-type caps discussed above, so as to facilitate the opening of twist-type caps in an easy, comfortable manner.
Some devices abandon the screw type configuration. For example, U.S. Pat. No. 3,675,805, issued in the name of Shane, discloses a snap open bottle cap. Similarly, U.S. Pat. No. 4,003,488, issued in the name of Moller, discloses a tear open bottle cap. Devices such as the '805 device and '488 device, however, have not won widespread acceptance by consumers, as is evidenced by their sparse usage.
A search of the prior art did not disclose any patents that read directly on the claims of the instant invention. Consequently, a need has been felt for providing an apparatus and method which overcomes the problems with conventional screw caps cited above.